Knife sharpener



Feb. 18, 1941.

R. M. NORTON KNIFE .SHARPENER Filed D90. 21, 1959 INVENTOR ATTORNEYPatented Feb. 18, 1941 FIKN F S B N M Ralph M. Norton, Brooklyn, Y.,-assignor to August W. Holmberg & Company, New York,

N. Y., a partnership consisting of Centre W. Holmberg and August W.Holmberg Application December 21, 1939, Serial No. 310,367

2 Claims. (Cl. 51--210) This invention relates to sharpeners for cutleryand is more particularly concerned with a knife sharpener for use inkitchens and shops.

The sharpener which is the subject of this in- 5 vention is providedwith a grinding wheel of an abrasive material having a recess in itsface and a conical guide member extending within the recess of thegrinding Wheel, both mounted for rotation about a common axis, and beingso spaced that the side of the guide member adjacent the grinding wheelissp-aced away from the outer edge of the recess of the grinding wheel.

In the past, many different types of knife sharpeners have been made butit was found that many of these sharpeners after a short period of use,dulled rather than sharpened the knives.

One of the objects of the present invention is to provide a cheap andsimply operated knife sharpener, which will continue to sharpen cutleryafter 20 a period of use, and which may be adjusted accurately inaccordance with the type of cutlery to be sharpened, and in accordancewith the type of edge desired.

For a better understanding of the invention reference may be made to theaccompanying drawing, in which- Figure 1 is a side elevational viewpartly in section and Figure 2 is a sectional View on the line 2--2 ofmy new knife sharpener.

In the accompanying drawing which illustrates a preferred form of my newdevice, l represents a shaft, which is held in place and sup-ported forrotation by a bracket H, which may be of any type or form to hold thedevice upon a wall or supporting surface such as a table or a counter.Mounted on the shaft are a series of grinding wheel l2, each having acentral recess l3 on 40 each face. Frusto-conical guide members l4 eachhaving a convex guiding surface extending within the adjacent recess arealso mounted on the shaft ID. The guide members l4 and the grindingwheels l2 are spaced apart the desired dis- 45 tance by a number of thinwashers 15 mounted on the shaft. A washer I6 and a nut ll tightened onthe threaded portion of the shaft I0 holds the guiding wheels and guidesin place and in the desired position. In the spacing of the grinding 50wheel and the guides, it has been found that when the guide member is sodisposed that a space of not more than .040 nor less than .005 of aninch is maintained between the guide member and the outer edge of therecess l8 in the grinding wheel the best results are obtained with theminimum of wear on the blade to be sharpened. a

In the operation of this device, the blade of a knife is placed againstthe guide member l4 until it comes into contact with the grinding 5wheel l2. The knife blade is then drawn back and forth, to contact withthe grinding wheel. Due to the fact that the grinding wheel and theguide members are spaced apart by the washers l5, it is possible whenthe. grinding wheel be- 10 comes Worn by use, to remove one or more ofthe washers which separate the grinding wheel and the guide members, andthus maintain the proper spacing between them. In the same way by theadjustment of the distance between the grinding wheels and the guidemembers, different types of blades may be accommodated and differenttypes of edges on cutlery may be obtained.

In the sharpener, subject of this invention, the illustrated shape ofthe grinding wheels has been found advantageous. It has been noted thatin the usual sharpener in which the guide member and the grinding wheelconverge, the elficiency is reduced as the grinding wheel wears down,and in many cases the knife is dulled rather than sharpened. In somedevices of the prior art it has been found that bits of the grindingwheel lodge in the vortex of the angle where the grinding wheel andguide members converge, and the bits of the grinding wheel thus dull andruin the 80 edge of the blade, rather than sharpen it. In the presentdevice, any abrasive particles resulting from the wearing away of thegrinding wheel will fall into the space formed by. the recess in thegrinding wheel. 85

I claim:

1. In a sharpening device, the combination of a shaft, a wheel mountedon said shaft, at least one face of said wheel being a grinding face,said wheel having a central recess extending inwardly 40 from saidgrinding face, a guide member mounted on said shaft and having a conicalface opposite the grinding face of said wheel extending into saidrecess, the conical face of said guide member being slightly spaced frombut sufficiently close to the inner edge of the face defining saidrecess that an article to be sharpened, when placed in the space betweenthe grinding face of said wheel and the guide member, will liesubstantially continuously in contact with the grinding face of saidwheel, and adjustable means providing for adjustment of said guidemember towards said wheel as the grinding face of said wheel wears,whereby the relative spacing of the conical face of said guide member tothe edge of the grinding 56 face defining said recess substantially maybe maintained.

2. In a sharpening device, the combination of a shaft, a wheel mountedon said shaft, at least one face of said wheel being a grinding face,said Wheel having a central recess extending inwardly from said grindingface, a guide member mounted on said shaft and having a conical faceopposite the grinding face of said wheel extending into said recess, theconical face of said guide member being between about .005 and .040 inchfrom the inner edge of the face defining said recess so that abrasiveparticles resulting from the wearing away of the grinding wheel may fallface defining said recess substantially may be maintained byprogressively removing said thin washers or shims.

RALPH M. NORTON.

